Method of manufacturing fiber metal



United States Patent 3,443 929 METHOD OF MANUFACTURING FIBER METAL Kiyoshi Kishi, Shigeki Iwauchi, and Isamu Saito, Tokyo,

Japan, assignors to Mitsuo Iwauchi, Tokyo, and Masako Shimizu, Takasaki, Japan No Drawing. Continuation-impart of application Ser. No.

354,389, Mar. 24, 1964. This application Nov. 30,

1966, Ser. No. 597,887

Claims priority, application Japan, June 11, 1963,

Int. Cl. C22b 15/00, 11/00 US. Cl. 75.5 5 Claims This application is a continuation-in-part of application Ser. No. 354,389, filed Mar. 24, 1964 now abandoned.

The present invention relates to the manufacture of extremely fine and long fibrous metal.

In the conventional manufacturing methods for fiber metal, in which, for instance, metallic foil was sheared or cut, very fine fibers could not be manufactured. The fibers thus obtained were e.g. 30-70 microns wide and their mechanical strength was very low.

Further as stated in SS. Brenner: The Growth of Whiskers by the Reduction of Metal Salts, Acta Metallurgica, vol. 4, January 1956, pp. 62-74, and other papers there is a method of producing fibrous metal, called whiskers, by hydrogen reduction of metal halides. But because this method did not employ carbonaceous material, as the present invention does, the yield was extremely low and it was impossible to utilize the product as an industrial material.

The invention provides a method of manufacturing fiber metal by mixing a metal compound, a halogen source and solid finely-divided forms of carbonaceous material, and applying heat thereto at a temperature lower than the melting point of said metal in a non-oxidizing atmosphere, to deposit a fibrous form of said metal on the carbonaceous material.

'In the present invention, the metal halide produced in the reaction system will be reduced and deposited on carbonaceous material so that fiber metal of whisker form or similar form 'will be obtained. It is aimed to present a method most suitable for the manufacture in large quantities and at low costs of the fiber metal which will have a uniformity in quality either in straight or spiral form, for example, of several microns in diameter and several hundreds of microns in length.

By way of illustration, a detailed explanation will be given regarding the manufacture of fiber metal in which the required metal is copper. As raw material there may be used a copper compound which can be halogenated, such as copper oxide, copper carbonate or copper hydroxide. :In the use of such a copper compound, heating is conducted together with a halide in addition to a carbonaceous material. For example, copper oxide such as cupric oxide, a halide such as cuprous chloride and solid finely-divided forms of carbonaceous material such as graphite are fully mixed at the rate of 100 parts, l0-20 parts and parts, by weight, respectively and heated at about 700 C. for -30 minutes with air blocked off. By this process, fine and long metallic copper fibers are deposited on the carbonaceous material.

The fiber metal obtained by the above mentioned process, usually, is a dense aggregation of fibers, each fiber being deposited on the carbonaceous material acting as the nucleus.

The shape of the fibers obtained is quite similar to that of the whiskers described in the aforementioned paper by Brenner.

The fiber metal obtainable by the method of the pres- 3,443,929 Patented May 13, 1969 ent invention is not limited to copper but includes silver and iron group metals or alloys thereof.

The fiber metal obtained by the method of the present invention is a product in the form of an aggregation of entwined fibers with considerable elasticity. The accompanying graphite or other carbonaceous material may be liberated from the fiber metal.

The various kinds of metal fiber produced by this method may be used, '(as mentioned, for example, in A. G. Metcalfe, C. H. Sump & W. C. Troy; Fiber Metallurgy, Metal Progress 67, March 1955, pp. 81-84) as metallic felt, which is formed by means of compacting or sintering, for the purpose of filtration, sound absorption, vibration prevention or catalyzing as well as raw material for fiber metallurgy in general. Where required, the fiber metal deposited on the carbonaceous material may be utilized as raw material of electrical materials, bearings, etc., without removing the carbonaceous material. The use of the fiber metal may be extended to molding with other materials such as ceramics, resins, metal powders, etc.

In the present invention, the metal compound may be selected from oxides, hydroxides, carbonates and silicates of the metals copper, silver, nickel, cobalt and iron which can be halogenated under the metal depositing conditions described below; the halogen source is a halogen or a halide which can halogenate the metal compound under the metal depositing conditions described below, such as chlorides, bromides, iodides or oxychlorides of said metals or other metals, hydroxylamine hydrochloride, ammonium chloride, hydrochloric acid, bromine, etc., the carbonaceous material may be finely-divided forms of graphite, charcoal, coal, active carbon, carbon black or other material, such as a paper, which can be carbonized by combustion. Usually, the metal compound, the halogen source and carbonaceous material are mixed to have 0.01-0.5 halogen/metal wt. ratio and have 0.08-06 carbon/ metal wt. ratio. Heat is applied thereto at a temperature lower than the melting point of said metal, conventionally at about 500900 C, for 4- 1 hour. The treatment is conducted in a non-oxidizing atmosphere, for instance, with ailr blocked ofi, in substantially nonactive gas.

Although the mechanism of reaction is not completely understood, it is believed that a variety of reactions occurs simultaneously. On theoretical grounds, it is conjectured that certain of these reactions require the initial presence of water. However, it has been observed that the process proceeds without any addition of water to the mixture. This may be due to the presence of at least a trace of water in the starting materials or in the atmosphere. In other words, said process proceeds even in the case where substantially dry starting materials as normal industrial products are used.

There are two methods of producing fiber alloy in accordance with the present invention. One method comprises using at least two metal compounds selected from the group consisting of oxides, hydroxides, carbonates and silicates of the metals copper, silver, nickel, cobalt and iron so that the metals from the two metal compounds are deposited on the carbonaceous material in the form of an alloy. The heating is carried out at a temperature lower than the melting point of the alloy to obtain a fibrous form of the alloy. Alternatively, or in addition the halogen source may be a halide of a metal selected from the group consisting of copper, silver, nickel, cobalt and iron but different from the metal of the metal compound so that an alloy is formed between the metal from the metal compound and the metal from the metal halide. Heating is carried out at a temperature lower than the melting point ofthe alloy of the metals to obtain a fibrous form of the alloy.

The invention is illustrated by the following examples but the present invention is not limited by these. In the examples, parts are parts by weight.

EXAMPLE 1 100 parts of cupric oxide, parts of finely-divided forms of graphite (100-325 mesh) and 3 parts of ammonium chloride are mixed. The mixture is inserted into a porcelain boat and heated for 1 hour in a cylindrical electric furnace controlled at 700 C. In this heating process the furnace is closed with air blocked off, and gases generated in the furnace are separated out of the furnace. Thus the aggregation of fibrous form of copper (85 parts) is obtained.

EXAMPLE 2 100 parts of copper basic carbonate, 8 parts of finelydivided forms of graphite (100-325 mesh) and 10 parts of cuprous chloride are mixed. The mixture is heated by using the same device described in Example 1 at 700 C. for 1 hour after first replacing the air in the furnace by nitrogen gas. The mixture is then heated at 800 C. for 2 hours while circulating nitrogen gas in the furnace, and residual chlorides are removed by volatilization. Thus the aggregation of fibrous form of copper (55 parts) .which does not contain any substantial amount of chloride is obtained.

EXAMPLE 3 100 parts of cupric oxide, 10 parts finely-divided forms of graphite (100-325 mesh) and 20 parts of cuprous iodide are mixed. The mixture is heated by using the same device described in Example 1 at 750 C. for 45 minutes with air blocked off. Thus the aggregation of fibrous form of copper (85 parts) is obtained.

EXAMPLE 4 100 parts of ferrosoferric oxide, 30 parts of glance coal (100325 mesh) and 50 parts of ferric chloride dehydrate are mixed. The mixture is heated by using the same device described in Example 1 at 900 C. for 2 hours with air blocked oli and a fibrous form of iron is produced while residual chlorides are removed by volatilization. Thus the aggregation of fibrous form of iron (100 parts) which does not contain any substantial amount of chloride is obtained.

EXAMPLE 5' 100 parts of ierrosoferric oxide, 30 parts of finelydivided forms of active carbon (100-200 mesh) and 30 parts of bromine are mixed. The mixture is heated by using the same device described in Example 1 at 850 C. for 1 hour with air blocked off. Thus the aggregation of fibrous form of iron (85 parts) is obtained.

EXAMPLE 6 100 parts of cobalt monoxide, 20 parts of finelydivided forms of active carbon (100-Q00 mesh) and 30 parts of cobalt chloride are mixed. The mixture is heated by using the same device described in Example 1 at 700 C. for 45 minutes with air blocked oif. The mixture is then heated at 800 C. for 3 hours while circulating carbon dioxide (containing 30% of carbon monoxide) in the furnace, and residual chlorides are removed by volatilization. Thus the aggregation of fibrous form of cobalt (90 parts) which does not contain impurities is obtained.

4 EXAMPLE 7 100 parts of nickel sesqui oxide, 20 parts of finelydivided forms of charcoal (100-325 mesh) and 30 parts of nickel chloride are mixed. The mixture is heated by using the same device described in Example 1 at 700 C. for 45 minutes with air blocked off. Thus the aggregation of fibrous form of nickel (100 parts) is obtained.

EXAMPLE 8 50 parts of cupric oxide, 50 parts of nickel monoxide, 10 parts of finely-divided forms of graphite (100-325 mesh) and 10 parts of cuprous chloride are mixed. The mixture is heated by using the same device described in Example 1 at 800 C. for 1 hour. Thus the aggregation of fibrous form of copper-nickel alloy parts) is obtained.

EXAMPLE 9 parts of cupric oxide, 10 parts of finely-divided forms of graphite (100-325 mesh) and 20 parts of silver chloride are mixed. The mixture is heated by using the same device described in Example 1 at 700 C. for 1 hour. Thus the aggregation of fibrous form of coppersilver alloy (85 parts) is obtained.

What is claimed is:

1. A method of manufacturing fiber metal which comprises mixing (1) at least one metal compound selected from the group consisting of oxides, hydroxides, carbonates land silicates of the metals copper, silver, nickel, cohalt and iron, with (2) a halogen source which can halogenate the metal compound, and (3) a solid finelydivided form of carbonaceous material, and applying heat thereto at a temperature lower than the melting point of said metal in a non-oxidizing atmosphere to halogenate said metal compound and to deposit a fibrous form of the metal on the carbonaceous material.

2. A method of manufacturing fiber metal according to claim 1, wherein the halogen source is a halide of said metal.-

3. A method of manufacturing fiber metal according to claim 1, wherein the carbonaceous material is a finelydivided form of graphite.

4. A method of manufacturing fiber alloy according to claim 1 which comprises using at least two metal compounds selected from the group defined in claim 1 and applying heat at a temperature lower than the melting point of the alloy of the metals to obtain a fibrous form of the alloy.

5. A method of manufacturing fiber alloy according to claim 1 which comprises using as the halogen source a halide of a metal selected from the group consisting of copper, silver, nickel, cobalt and iron but difierent from the selected metal of the metal compounds defined in claim 1, and applying heat at a temperature lower than the melting point of the alloy of the metals to obtain a fibrous form of the alloy.

References Cited UNITED STATES PATENTS 1,104,907 7/:1914 Laist 75-77.

OTHER REFERENCES Acta Metallurgica, vol. 4, January 1956, pp. 62-74.

L. 'DEWAYNE RUTLEDGE, Primary Examiner.

T. R. FRYE, Assistant Examiner.

U.S. Cl. X.R. 

1. A METHOD OF MANUFACTURING FIBER METAL WHICH COMPRISES MIXING (1) AT LEAST ONE METAL COMPOUND SELECTED FROM THE GROUP CONSISTING OF OXIDES, HYDROXIDES, CARBONATES AND SILICATES OF THE METALS COPPER, SILVER, NICKEL, COBALT AND IRON, WITH (2) A HALOGEN SOURCE WHICH CAN HALOGENATE THE METAL COMPOUND, AND (3) A SOLID FINELYDIVIDED FORM OF CARBONACEOUS MATERIAL, AND APPLYING HEAT THERETO AT A TEMPERATURE LOWR THAN THE MELTING POINT OF SAID METAL IN A NON-OXIDIZING ATMOSPHERE TO HALOGENATE SAID METAL COMPOUND AND TO DEPOSIT A FIBROUSS FORM OF THE METAL ON THE CARBONACEOUS MATERIAL. 